Low capacitance transformer



Oct. 9, 1962 `s. R. HoH

LOW CAPACITANCE TRANSFORMER Original Filed Feb. 2l, 1956 I NV E N TOR. fare/5,990

ni-c.,-

kloss of essential electrical characteristics.

United tats the Air Force Original application Feb. 21, 1956, Ser. No. 567,038. Dr-

vided and this application Aug. 7, 1958, Ser. No.

4 Claims. (Cl. 336-182) (Granted under Title 35, U.S. Code (i952), sec. 266) The invention described herein may be manufactured and used by or for the United States Government for governmental purposes without payment to me of any royalty thereon.

This application forms a division of my copending application Serial No. 567,038, tiled `February 2l, 1956. The invention relates to the development of a low distributed capacitance transformer suitable for use at higher frequencies than is` possible with conventional, commercially available components.

An object of this invention is the production of a novel transformer which is of very small size without a sacrifice of elec-trical characteristics.

Another object of this invention is the production of magnetically coupled transformer which does not normally require shielding or insulation.

A further object of this invention is to provide coupling devices utilizing non-'conducting ferromagnetic ferrites or powdered iron.

A further object of this invention is the production of a novel transformer which is easily manufactured and is low in cost.

'Fliese `and other advantages, features and objects of the invention will become more apparent from the following description taken in connection with the illustrative embodiments in the accompanying drawings, wherein:

FIG. 1 shows `an end view of a miniature high-frequency transformer in section; and

FIG. 2 illustrates a top View partly in section of the embodiment of FIGURE 1.

Miniaturization of components for high frequency work is aided by the utilization of the properties of the nonconducting ferromagnetic ferrites; accordingly, the novel design of a low distributed capacitance transformer of FIGURES 1 and 2 achieve this 'desired result without a The embodiment disclosed in the gures consists of a pair of at spiral conductors 24 and 25, comprising the transformer prim-ary and secondary, in a coplanar relationship on a non-conducting `ferromagnetic ferrite disc or plate 26. Disc 26 provides the coupling between the primary and secondary. Additional ferrite discs 27 `and 28 may be provided to increase the Q of the transformer and also results in providing a shielding effect.

Conductor 24, which is a duplicate of conductor 25, shown in FIGURE 1, may be formed in many ways to conform to standard mass production techniques. For example, since a non-conducting ferromagnetic ferrite is used, conductors 24 and 25 need not be insulated, thus allowing for a closer relationship between the elements comprising the transformer. Further reduction of the spacing and transformer cost may be achieved by utilizing stampe-d sheet metal conductors `or printing the conductors ydirectly on the discs. Another method which is admirably suited for high frequency applications involves the reduction of the ferrite in the shape of the conductors to metal to forrn the conductors.

Since the stray flux of the transformer is of a very low value, shielding will not normally be required, thus aiding in the reduction of size of the transformers without sacrificing the Q factor or other electrical characteristics.

While ferromagnetic ferrites because of their high permeability are the preferred magnetic materials for the above circuit elements, powdered iron materials may also be used for low frequency applications.

Although the invention has `been described with reference to particular embodiments, it will be understood to those skilled in the art that the invention is capable of a variety of alternative embodiments within the spirit and scope of the yappended claims.

I claim:

1. A trans-former for high frequency application comprising a disc of non-conducting ferromagnetic material and a pair of fiat, generally spiral shaped conductors in -a rcoplranar relationship to said disc, said conductors being in juxtaposed alignment along one surface only of said disc.

2. A device as dened in claim 1 including a pair of discs arranged to cover said conductors.

3. A transformer comprising a dat disc of magnetic material, a primary winding of a flat, generally spiral shape and a secondary winding of a dat, generally spiral shape, said windings being arranged on one side only of said `disc in a coplanar relationship.

4. A device las defined in claim 3 including a pair of llat discs of magnetic material arranged in a coplanar relationship to cover said primary and secondary.

References Cited in the file of this patent UNITED STATES PATENTS 2,114,031 Rust et al. Apr. 12, 1938 2,474,988 Sargrove July 5, 1949 2,850,707 Wroblewski et al Sept. 2, 1958 2,910,662 Rex Oct. 27, 1959 National Bureau of 1947, particularly pp. 

